import rabbitpywith rabbitpy.Connection() as connection:    with connection.channel() as channel:        channel.prefetch_count (10)        unacknowledged = 0        for message in rabbitpy.Queue(channel, 'test-messages')            message.pprint()            unacknowledged += 1            if unacknowledged == 10:                message.ack(all_previous=True)                unacknowledged = 0